Adjustable-point lathe-centeb



'7 e. c. noamsou.

ADJUSTABLE POINT LATHE CENTER.

APPLICATION TILED IIAILZT, 1919.

1,317,894. Patented Oct. 7,1919.

, center-point.

' omen]: cam. aozennson, or nnraorr, MICHIGAN.

ADJUSTABLE-POINT LATHE-CENTER.

Specification of Letters Patent.

Patented Oct. 7, 1919.

' Application filed March 27, 1919. Serial No. 285,691.

To all whom it may concern:

Be it known that I, GIRARD C. RoB NBoN,

a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented new and useful Improvements in Adjustable-Point Lathe- Centers, of which the following i a specification.

, This invention relates to lathe centers, and more specificall to an improved construction in which 11 e center-point is adjustable longitudinally within the centerpomt holder.

One object of this invention is to provide an improved adjustable center for lathes, rinders or other machines, which renders it unnecessary to move the tail-stock when changing center-pins or center-points.

Another object is to provide an improved device of this character which accomplishes a great saving of time and material in the peration of re grinding or re-pointing the Other objects and advanta 3 ma become apparent to persons who r the ollowing details of description in connection with the accompanying drawings, in which:

Figure 1 is a side elevation of a centerpoint holder and its adjuncts constructed and assembled in accordance with the present invention.

Fig. 2 is a perspective view of the center-- screw-threaded for meshing with the screw or adjuster 7 the rear portion of the hollow being enlarged, as indicated at 10, to protect the screw from mutilation and the front end of the hollow being cylindrical so as to conform to the convex surface of the centerpin 6. The center-point holder 5 is provided with a radial aperture 11 which receives the set-screw S, and this aperture 11 is in open communication with the center-pin seat which is formed by the 'front portion of the hollow or bore through the center-pin holder 5. The set-screw 8, therefore, may be turned and thereby caused to exert a pressure against a sl-abbed surface 12 of the pin 6 so as to secure the latter against turning in the body 5. The slabbed sur face is not essentially plane as shown, but may consist of any cut-away or slabbed surface which breaks the cylindrical surface and coacts with the set-screw for preventing the center-point from turning.

The screw 7 is operatable by any appropriate means, so as to adjustthe center-pin by pushing it forward to the desired position, and the set-screw 8 co-acts with the screw 7 to hold the center-point rigid with relation to the center-point holder.

The body 5 is preferably carbonized and hardened steel and is taperedrearwardly from a portion adjacent to its front end, the taper of this portion corresponding to that of the Ion itudinal bore of a standard tailstock-spin le, although this taper may be varied by the manufacturer when desirable.

The center-point is preferably made of high-speed steel and therefore, it is not requlred that another point be substituted therefor until it has undergone a large amount of hard and constant uses. However, when it is necessary or desirable to remove the center-point 6, the set-screw 8 may be loosened to permit the center-point to be withdrawn from its seat.

What I claim as my invention is:

' 1. The combination of a center-point holder, acenter-point longitudinally adjustable therein, adjusting means in the centerpoint holder for effecting the longitudinal adjustment of the center-point, and clamping means to coact with said adjusting means to secure said center-point in rigid relation to said centeroint holder in the different adjustments 0 the center-point.

2. The combination of a center-point holder, acenterint longitudinally adjustable therein, an having a slabbed surface extending therealong, means in the centerpoint holder for adjusting the center-point, and a set screw 0 erable in said centeroint holder and settab le against said slab'be surface to prevent rotation of the center-point and to coact withsaid means in preventing accidental longitudinal movement of the center-point.

, 3. The combination of a center-point holder having a bore extending longitudinall therethrough. a renter-point having a slab ed side, a, screw threaded adjuster, and a set screw, the fOIWHid end of said longitudinal bore instituting a seat for said center-point, a part Of Said bore behind said seat being screw-threaded and meshing with the threads of said adjuster, said oeiiterpoint holder having: a radial bore which is screw-threzuled and in which said set-screw operates to bear against said slabbed side of the center-point.

GIRARI) CARL ROBINSON. 

